The invention resides in an internal combustion engine with an exhaust gas turbocharger, an intercooler and a control unit with a temperature sensor sensing the engine operating temperature for controlling the supply of compressed air to the engine.
DE OS 3929 123 discloses such an internal combustion engine wherein the air intake pipe includes an intercooler and a by-pass duct for by-passing the intercooler. The charge air flow by-passes the intercool until the engine has reached a predetermined operating temperature under the control of a control arrangement which is dependent on the engine operating temperature. When this operating temperature is sensed by a temperature sensor mounted on the engine, the control arrangement switches the charge air flow to pass through the intercooler.
The by-pass duct by-passing the intercooler is connected to the intake pipe upstream and downstream of the intercooler by means of a switching device arranged in the intake pipe. Such an arrangement requires the control of two spaced switching devices which is complicated and requires an expensive design for the by-pass duct for by-passing the intercooler.
These disadvantages are partially eliminated by the arrangement disclosed in DE OS 36 27 686 wherein a by-pass line branching off the charge air pipe and by-passing the intercooler is controllable by a single switching device. No switching device is provided at the downstream end of the by-pass line. This arrangement is simplified as only one switching device is provided and only one switching device needs to be controlled but there is still the need for the additional by-pass conduit. It is also noted that, at the jointures of the by-pass conduit, that is, where it branches off the charge air pipe, as well as where it rejoins the charge air pipe, there are unfavorable air flow conditions because of restrictions in the relatively small air flow passages.
It is the object of the present invention to provide for an internal combustion engine with an exhaust gas turbo-charger and an intercooler in which the charge air is cooled after the engine has reached a certain operating temperature but which is by-passed during engine warm-up including an arrangement for controlling the charge air flow which is simple in design, inexpensive to manufacture and reliable in operation.